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Hey there guys! First post here. I've been battling with my 1980 KZ440A LTD for about 3 weeks now and I'm not sure what's going on. Good fuel flow from the tank, good spark, and good air mixture. It started kicking and bucking real bad till it finally just totally died on me. Chased the issue till I found a bad float needle in one of my carbs. Put them back in, it ran for about 2 minutes, then died again. Same thing is still happening to this day....when I empty the bowls and remove the carbs to see whats going on in there, I put them back on and the thing runs like a top for about 2 minutes...then cuts out. It seems to be when the bowls are filled. The float level seems to be dead on, mixture screws are turned out 1.75 turns, and everything else looks good in the carbs...HELP!!

Jmcjunkin3 wrote: . . . float level seems to be dead on . . . .

Has fuel level been verified via clear-tube tests?

Good Fortune!

Yes. Appears to be about 3 to 4mm from the bottom of the carbs. I made marks on the carbs where the fuel level was so I could go back and measure if needed, for now I just eyeballed it.

Jmcjunkin3 wrote: . . . 1980 KZ440A LTD . . . Good fuel flow from the tank, good spark, and good air mixture. . . runs like a top for about 2 minutes...then cuts out. . . .

Insufficient valve clearance could cause the reported symptoms.
A valve that's barely sealing when the engine's cold can begin leaking as the engine warms.

Good Fortune!

That would make sense...I'll have to check my clearances. Also I wanna go start the bike cold to see if it even starts...that would eliminate my theory about it dying once the bowls are full. Thanks!!

If you just had a float valve problem before this problem appeared, my guess is that the bowl is overfilling when the engine is running (vibration causing the float valve to leak / stay open); the engine is flooding on that cylinder. Believe it or not, my riding mower engine does that quite frequently...starts to spit and cough, hammers, black smoke, then dies. Grass blades get past the air filter sometimes and prevents the float valve from closing.

The float level seemed to be dead on when I checked it, could they still be overfilling? If so, why would they be doing this/how do I fix it? Thanks!

The float valve might only be leaking when the engine is shaking everything (running), so it looks fine when tube testing it static. Did you replace the valve needle and seat as a set, or only the needle? It is recommended you should always replace both as a set with new parts. Also make sure the little spring plunger on the new needle is working as it should. I have bought new needles that the spring was weak or sticking right out of the package - I have about 10 of them, in fact, in a parts drawer in my shop (and no, I don't have a good reason why I kept them). The only times I've ever had to adjust float tang / levels on a Honda or Kawasaki was if the carbs needed replacement floats, or if I was replacing carbs completely, or if I had to change the float levels (and just about everything else in the carburetors) to tune / compensate for other engine modifications like higher compression ratio, racing cams, etc. (some Keihin CV carb floats are made entirely of plastic and can't be adjusted at all).

If the bowls are overfilling even though the fuel level looks correct when doing the clear tube test you probably do have a sticky float valve. You can clean the float valve orifice with a Q-tip and some carb cleaner, and also clean the needle. Do NOT use anything abrasive or you will create a leakage problem. Do you have a fuel filter on the bike? If not, it would be a good idea to install one to prevent any small debris in the fuel or fuel tank from fouling the float valve. Ed

Hey guys. I only replaced the needle because the seat didn't come with the kit I had. I'll pull the carbs tonight and clean everything up real good...see where that gets me. Appreciate all of the help!
-Jim

I think you have Keihin CV carbs in which case the seats are pressed in and not replaceable.

If the Q tip and carb cleaner which Ed suggested does not work then try Brasso on the Q tip and flush with carb cleaner. I have hsd good results doing this.

I'm assuming you will have the carbs off the bike for this so when finished and before you put the float bowls back on turn the carbs upside down, put the fuel line in your mouth and blow as hard as you can. If the float needle is seating properly then it takes a lot of lung power lift the needle and to hear air escaping.

Yeah I kind of assumed they were pressed in due to the material they're made of. As for the upside down test, I've done it everytime before the carbs have gone back in and they seal perfectly. I got air escaping once but I fixed it. Carbs are coming out tonight!